Manufacture of tubes from fibrous pulps



Feb. 21, 1933. A, MAGNANI 1,898,881

MANUFACTURE OF TUBES FROM FIBROUS PULPS I Filed Oct. 24, 1950 s Sheets-Sheet 1 Z; vewior.

3 Sheets-Sheet 2 A. MAGNANI MANUFACTURE OF TUBES FROM FIBROUS PULPS Filed Oct. 24, 1950 Feb. 21, 1933.

Feb. 21, 1933. A. MAGNANI ,8 8 8 MANUFACTURE OF TUBES FROM FIBROUS PULPS Filed 001?. 24, 1930 I 3 Sheets-Sheet 3 my? Z ibmz Patented Feb. 21, 1933 ALESSANDRO MAGNANI, OF OASALE MONFEBRATO, ITALY MANUFACTURE OF TUBES FROM IE'IBIRO'US PULPS Application filed October 24, 1930, Serial No. 491,056, and in Italy December 9, 1929.

The invention relates to the manufacture of tubes from fibrous pulps and provides improved methods of manufacture and apparatus for carrying these methods into effect.

The methods used at present in the manufacture of tubes of various forms from pulps of fibrous substances made into a paste with a binder, such as asbestos and cement pulp, have many disadvantages which limit their practical application.

The method forming the subject of the present invention facilitates the rapid manufacture of tubes of the most varied shapes and dimensions, particularly socketed pipes;

the said method does not sufi'er from the disadvantages hitherto met with and it can be carried-into effect by means of practical and' very simple apparatus of moderate cost.

Pulps which can be used in this method of manufacture of tubes are aqueous pulps of any nature containing a suitable binder, such as mixtures of asbestos and cement, papier mach, cork pulps and the like.

According to the invention the pulp is 5 spread in layers on a rotating matrix roller and after formation the tube is ressed thereon and on completion drawn 0E.

The pressure is usually exerted by a shaping roller rotating tangentially to the matrix roller, and a sufficient vacuum may be created inside the matrix roller to assist the formation of an initial layer of pulp and the partial drying of the next layers wound on.

The improved apparatus according to the invention comprises a matrix roller covered with a cage of wires stretched longitudinally. Preferably the cage is so fixed to the roller that on completion of the tube the roller may be drawn out from the wire cage, the cage then being removed from the interior of the tube. Perforations are advan tageously made in the surface of the roller and exhausting means are provided to draw off moisture from the tube.

According to a further feature of the invention the shaping roller is made in sections loosely mounted on a shaft rotating at a higher speed than that corresponding to frictional engagement of the rollers.

'show in end and side elevation respectively The distribution of the pulp may be undertaken by a pump having its plunger controlled by a guide so as to give the correct dlstribution for the purpose required.

The pressing of the tube is in some cases carried out in addition by a double walled bell with flexible inner wall capable of bemg pressed against the tube by the action of a pressure fluid admitted between the two walls of the bell.

The accompanying drawings show diagrammatically an example of apparatus according to the invention.

In the drawings:

Fig. 1 shows in plan the apparatus servmg for the formation of the tubes.

Fig. 2 is an end elevation of the apparatus shown in Fig. 1.

Fig. 3 is a View of the matrix roller partly '0 in section.

Fig. 4 is a view of the shaping roller, partly broken away and partly in section.

Fig. 5 is an elevation partly in section of the pressing machine, while Figs. 6 and 7 7 the cradle and other apparatus serving for drawing off the tube from the matrix roller.

Referring to Figures 1, 2 and 3, the formation of the tubes takes place by applying to the matrix roller 1 successive layers of pulp; A shaping roller 2 rotates tangentially to the matrix rollerand causes the lamination of the pulp by pressing it out in the form of a layer, and the excess water is eliminated by a vacuum in the inside of the matrix roller; a suitable pulp distributing device, which in the example described takes the form of a reciprocating pump 3, ensures the required distribution of the layer of pulp to suit the diameter and thickness of the'tube at each part.

The matrix roller 1 is a hollow metallic cylinder 4, having on its external surface grooves 5, at the bottom of which are perforations 6 communicating with the interior. The said cylinder is covered by a cage of metal wires 7 stretched in a direction parallel to the axis of the said cylinder and supported on the external wall of the cylin- 1 0 der so as to reproduce the internal shape of the tube which it is desired to make.

The said wires are fixed b their extremities to fixing plates 8, 9. T e plate 8 abuts against the end 10 of the cylinder 4, while the plate 9 is bolted against the flange 12 of the cylinder 4 by a set of tension bolts 11.

At one of the extremities oft-he cylinder 4 is provided a ring 13 with packing, and holes 14 are provided through which air may be exhausted by any suitable means to produce a vacuum inside the cylinder. In general it will be sufiicient to connect to the pipe 15 a suction pump of any suitable type.

The shaping roller 2 shown in Figure 4 is made up of a plurality of elements 16, 17 loosely mounted on the shaft 18: the outer surface of these elements is provided with grooves or riflings 19 preventing the pulp from adhering to the said roller. The number of elements may vary according to requirements and to suit the outline of the tube to be formed, because the peripheral speed of each of the elements must be equal at each instant to that of the part of the tube in contact with it; moreover this speed will vary during the formation of the tube on account of the increaseof thickness of the pulp layer. For this reason the shaft 18 on whichthe elements 16, 17 are loosely mounted rotates at a speed slightly higher than that corresponding to the movement of the shaping roller without friction against the matrix roller. In the case of a cylindrical tube the said elements are reduced to a single one. It should be observed that in practice two or more shaping rollers can be used which may act if necessary as compressing or burnishing rollers.

The rollers described (matrix and shaping) are mounted on hearings on a frame 20; the bearings 21 of the matrix roller 1 are fixed, while the bearings 22' of the shaping roller 2 can slide transversely along suitable guides 23; the movements of the bearings 22 of the shaping roller 2 are controlled by pistons 24 moving in cylinders 25 into which may be sent a pressure fluid so as to vary the distance between the shaping roller and matrix roller.

The distribution of the pulp is carried out in a very simple manner, by means of a pump 3 mounted on the carriage 26 rolling along a guide 27; its piston is moved against spring pressure by the guide 28 along which rolls the pulley 29 mounted at the end of the rod 30 of the said piston.

The suction pipe 31 of the pump 3 is inserted in a trough 32 along the side of the machine containing the pulp previously prepared and stirred by a shaft 33 provided with paddles.

The distributing tube 34 serves to spread the pulp between the two rollers as may be clearly seen in Fig. 2 and the curvature of the guiding rod 28 is so made as to permit the distribution ofthe pulp in larger quantity where a greater thickness of the wallof the tube is necessary or where the diameter is greater. End lates 35, 36 prevent the pulp from spreadlng laterally beyond the ends of the rollers; the said plates have openings 37 to permit the displacement of the shaping roller towards and away from the matrix roller.

The operation of formation of the tube takes place in the following manner. The pulp being ready in the trough 32, the rollers are set into movement and the pump 3 slides in a direction parallel to the axes of the rollers along the guide 27. The guiding rod 28 causes the pump to act and to distribute the pulp in the space between the rollers 1 and 2 and the side walls 35, 36; the matrix roller becomes covered gradually with successive layers of pul spread upon it by the shaping roller 1, wliile the excess water is eliminated through the layer of pulp by the action of suction exerted through the packed ring 13 in the interior of the matrix roller. As the thickness of the tube increases the bearings of the shaping roller move gradually away from the bearings of the matrix roller.

When the operation is completed and the distributed layer of pulp has attained the desired thickness, the pressure fluid is sent to the opposite ends of the pistons 24, thus moving the shaping roller away from the matrix roller. After that the matrix roller is lifted from its bearings and it is passed to the compression machine serving for drying the tube by removing the water still present.

This compression machine is shown in Figure 5 and comprises uprights 4O fixed to the ground and having a height more than twice the length of the tube; along the said uprights slides a double-walled bell 41 which can be raised or lowered b means of any suitable lifting arrangement. The bell comprises an external metallic casing 42 provided with lugs 43, 44 sliding along the uprights 40 and an internal elastic wall 45 fixed by its ends between the flanges 46, 47 and plates 48, 49: through the pipe 50 a pressure fluid is admitted between the two walls 42, 45 of the bell as required.

The matrix roller 1, with the partly formed tube on it, is arranged vertically between the uprights of the machine. then the bell 41 is lowered to the position indicated in the lower part of Fig. 4. By admitting the pressure fluid between the walls of the bell the inner elastic wall is compressed and spreads itself on the external surface of the tube, compressing it. The water running out on account of the compression exerted is removed through the pipe 15 of the matrix roller. When the pressing is completed the -oft pressureof the fluid between the walls 41 is reduced and finally vacuum is applied to bring back the elastic wall into its normal positlon and to detach it from the external surface of the tube to which it adheres; finally thebell is raised away from the tube.

The tube, still mounted on the matrix. roller, is thenv laid on a suitable cradle shown in Figures 6 and 7 for removal from the roller. The said cradle is made up of two lateral, walls 51, 52, between which is stretched a flexible sheet 53 formed of wire gauze, fabric, cloth, netting or the like. A clamp 55 of suitable form holds the plate 8 of the wire cage surrounding the matrix roller, while another clamp 54 engages the flan e 12 of the inner metallic cylinder 4 fie matrix roller. By means of the cable 56 and suitable means, as for example a capstan or winch or the like, the internal cylinder 4 is drawn out from the wire cage; then the clamp 54 is fixed to the end plate 9 of the cage and a further operation of the winch detaches the wires of the said ca e from the inner wall of the tube. Final y the clamp 55 is opened so that the complete wire cage can be taken out. The completed tube may be left on the cradle if required until it is finally set or matured.

The constructional details of the apparatus necessary for the application of the method have been indicated simply by way of example and they may be replaced by other equivalentarrangements which may be found more suitable in practice to carry out the duty imposed on them. Further, the operation of compression by means of the pressing bell described may be omitted if the action of suction caused in the interior of the matrix roller is considered sufficient.

Any suitable material may be used inthe manufacture of tubes according to the invention, for example mixtures of asbestos fibres and cement, papier mach, mixtures of rubber with vulcanizing ingredients or the like; it is clear that in the last named case the method must be partially modified in order to make this special application possible, say by the addition of heat circulation or the substitution for the pressing bell of vulcanizing apparatus, if required, without departing from the spirit of the present invention.

I am aware that prior to my invention a process for manufacturing tubes of fibrous materials with one layer only of matter was known.

I know also that processes have been proposed using an endless ribbon or belt. I, therefore, do not claim such a process broadly; but

I claim:

1. In a machine for manufacturing tubes from fibrous pulps, a rotating matrix roller consisting of an internal hollow core having permeable walls and sha ed substantially as the internal surface 0 the tubesto be forme and an external cage of longitudinally stretched wires.

2. In a machine for manufacturing tubes from fibrous pulps, a rotating matrix roller consisting of an internal hollow core having a plurality of circular rooves on its outer surface and a number 0 perforations at the bottom of said rooves communicating with the interior, and of an external cage of longitudinally stretched wires.

3. In a machine for manufacturing tubes from fibrous pulps, the combination of a rotatin matrix roller consisting of an in ternal hollow core having permeable walls and shaped substantially as the internal surface of the tubes to be formed and an external I cage of longitudinally stretched wires, with a movable plunger pump for distributing the pulp, a guide for the pump in the direction of the axis of the matrix roller, a second guide controlling the stroke of the plunger to give the necessary distribution of the pulp for the diameter and thickness of the tube required at any point.

4. The method of forming tubes of fibrous material, which comprises formin a dense mortar of said fibrous material with water and a suitable binder, moulding biylnrolling said mortar to form a leaf, win g sai leaf helically in successive layers one on the other, and forcing by suction part of the water content from the latest superposed layer thereof to and through the preceding layers.

5. The method of forming tubes of fibrous material, which comprises formin a dense mortar of said fibrous material with water and a suitable binder, moulding b rolling said mortar to form a leaf, winding said leaf helically in successive layers one on the other, forcing by suction part of the water content from the latest superposed layer thereof to and through the preceding layers, and compressing the formed tube to squeeze from it part of the water remaining in said layers.

6. A machine for manufacturing tubes from fibrous pulps, comprising in combination a rotating matrix roller having permeable walls and transversal sections non-uniformly variable from point to point of its length, suction means for exhausting the air from the inside of said matrix roller, slide bearings for the shaping roller, cylinder plungers acting in said bearings to press the shaping roller against the matrix roller when a pressure fluid is admitted on said plungers,

and a pump for distributing the pulp besaid matrix roller, and shapin rality of circumferential grooves on the outer surface of said elements.

8. A machine for manufacturing tubes from fibrous pulps, comprising in combination a horizontally mounted rotating matrix roller having permeable walls, suction means to produce a low pressure in said matrix roller, horizontally mounted shaping rollerspressed against said matrix roller, and means to deposit the pulp in the trough formed between the matrix roller and the shaping rollers.

9. A machine for manufacturing tubes from fibrous pulps, comprising in combination a rotating matrix roller having permeable walls and transversal sections different from point to point of its length,

suction means to produce a low pressure in rollers rotating tangentially to said matrix roller and having a plurality of transversal sections of different diameters, each section of the shaping rollers being independently rotatable.

10. A machine for manufacturing tubes from fibrous pulps, comprising in combination a horizontally mounted rotating matrix roller having permeable walls, a suction pump for exhausting the air from the inside of said matrix roller, a shaping roller pressed against said matrix roller and mounted on a horizontal axis parallel to the matrix roller, and another pump to supply and deposit the pulp in the trough formed between the matrix roller and the shaping roller.

11. A machine for manufacturing tubes from fibrous pulps, comprising in combination a horizontally mounted rotating matrix roller having permeable walls, suction means to produce a low pressure in said matrix roller, horizontally mounted shaping rollers pressed against said matrix roller, means to deposit the pulp in the trough formed between the matrix roller and the shaping rollers, and means for moving the pulp depositing pump axially of the rollers.

12. A machine for manufacturing tubes from fibrous pulps, comprising in combination a horizontally mounted rotating matrix roller having permeable walls, a suction pump for exhausting the air from the inside of said matrix roller, a shaping roller pressed against said matrix roller and mounted on a horizontal axis parallel to the matrix roller, another pump to supply and deposit the pulp in the trough formed between the matrix roller and the shaping roller, and means for moving the pulp supplying and depositing pump axially of the rollers.

13. A machine for manufacturing tubes from fibrous pulps, comprising in combination a horizontally mounted rotating matrix roller having permeable walls, suction means to produce a low pressure in'said matrix rol er, horizontally mounted shaping rollers pressed against said matrix roller, means to deposlt the pulp in the trough formed between the matrix roller and the shaping rollers, means for moving the pulp depositing pump axially of the rollers, and means for varying the rate of de osition of the pulp as the pulp depositing means moves axiall of the rollers.

14. A machine or manufacturing tubes from fibrous pul 8, comprising in combination a horizonta y mounted rotating matrix roller having permeable walls, a suction pump for exhausting the air from the inside of said matrix roller, a shaping roller pressed against said matrix roller and mounted on a horizontal axis parallel to the matrix roller, another pump to supply and deposit the pulp in the trough formed between the matrix roller and the shaping roller, means for moving the pulp supplying and depositing pump axially of the rollers, and means for varying the rate of discharge of the pump as the pump is moved axially of the rollers.

15. In a machine for manufacturing tubes from fibrous pulps, a shaping roller consisting of a shaft and a number of elements loosely mounted on the shaft, said elements being independently rotatable.

16. In a machine for manufacturing tubes from fibrous pulps, a shaping roller consisting of a shaft and a number of elements loosely mounted on the shaft, said elements being independently rotatable and certain of said elements being of different diameters.

In testimony whereof, I afiix my signature.

ALESSANDRO MAGNANI. 

